This invention relates to slitter machines for slitting a wide film sheet wound on a core in a roll in order to obtain narrower desired widths of the film sheet, and more particularly concerns a slitter machine for slitting desired narrow strips from a wide roll of a tacky film resist sheet having a cover sheet on top and a separator sheet on the bottom, which film resist sheet is to be laminated onto metallic substrates used in semiconductor devices.
Photosensitive film sheets are supplied in a roll which may be five inches to twenty inches wide. However, the strips required for laminating onto metallic substrates may vary between one inch wide to five inches wide, in accordance with the width of the metallic substrate to which it is to be laminated.
But it is not feasible to buy strips which are pre-cut to the desired widths. To do so, the manufacturer of the semiconductor devices would be required to inventory many widths of strips which would be inconvenient and expensive, and would also be required to pay a premium to the supplier of the strips because of the extra steps required to make the strips into the desired widths.
The rolls of photosensitive film sheets referred to are comprised of a tacky layer of photosensitive polymer material, a top protective layer of polyester material, and a bottom separator layer of polyolefin material, although sometimes the separator layer may be omitted. Accordingly, the photosensitive film layer, which is sticky or tacky, is sandwiched between two layers, the cover layer and the separator layer, which protect it. The separator layer is removed before laminating the photosensitive film layer onto the metallic substrates, and the cover layer is removed after the photosensitive film layer is laminated onto the metallic substrates.
However, the cutting or slicing the roll of these composite layers, the tacky photosensitive film layer and its protective top cover and separator bottom cover, poses a number of problems.
It is difficult to slice the composite layers in a precise width and in a true vertical plane.
If a knife blade penetrates too deeply into the roll of overlapping layers, the tacky photosensitive film layer adheres to the sides of the knife blade, which interferes with its ability to cut the composite layers in a clean vertical path. Also, the photosensitive film layer is damaged along its edge, making it difficult or impossible to subsequently laminate the photosensitive film layer onto the metallic substrates.